Project Summary/Abstract This is a critical time for the advancement of HIV prevention and care. In the U.S., testing has become widespread, and most persons who are living with HIV (PLWH) are aware of their status. Antiretroviral therapy (ART) has become so simple and tolerable that most PLWH can achieve ?undetectable? HIV levels, reaping benefits for their own health and becoming ?untransmittable? to their partners. Pre-exposure prophylaxis (PrEP) is a safe and efficacious method of reducing HIV acquisition. However, the point-of-care (POC) HIV tests that are FDA-approved still fail to recognize highly infectious persons with acute infection, and real-time adherence counseling options for HIV treatment and PrEP are limited. HIV continues to have disproportionate impact among men and transgender persons who have sex with men, with subpopulations like racial/ethnic minorities and methamphetamine-users being at particularly high risk. Thoughtful implementation of POC nucleic acid tests (NAT) has potential to address some of the remaining challenges in HIV prevention and care. The project proposed for this Cooperative Agreement (U01) will develop, implement, and evaluate models for use of POC NAT among HIV-negative persons seeking HIV testing, PEP, and PrEP and HIV-positive persons in community and clinical settings. Following a period of formative work to establish protocols, SOPs, data collection instruments, and data analysis plans, Aims #1 and #2 will evaluate the sensitivity and specificity of a qualitative POC NAT in persons not known to be HIV-positive and will determine the impact of its use on PrEP uptake and persistence among persons testing HIV-negative and on time to HIV continuum of care outcomes among persons testing newly HIV-positive. Aim #3 will implement a POC NAT-tailored behavioral intervention to evaluate impact on time to virologic suppression among PLWH receiving ART. Aim #4 will quantify the acceptability and feasibility of implementation of POC NAT in community and clinical settings and collect cost and related data for cost-effectiveness analyses. Finally, in Aim #5, a distinct but related study will compare the sensitivity, specificity, and agreement of multiple POC NATs over a range of HIV RNA levels. This project will collect data on the performance of POC NAT and associated clinical outcomes, patient and provider perspectives regarding acceptability and feasibility, and implementation science outcomes including cost effectiveness. Employing a research team with substantive expertise in HIV testing including POC NAT, PrEP and HIV clinical care and programming, community and public health expertise, medication adherence interventions, and cost-effectiveness analysis, this collaboration will work to implement POC NAT with the goal of documenting real world test performance and developing models to improve HIV care and prevention outcomes in the U.S.